No, you shouldn’t use a third party USB to Serial converter. Custom made, please see note below.
You cannot use other FTDI or generic programming adaptors, as most of them do not use the same reset technique required for 4D Processors, and will either not work correctly, or will 'brick' the 4D Processor. It is highly recommended you do not even attempt to try this at risk of damaging your modules processor.
4D Programming Adaptors or Cables are available on the 4D Systems website, or from distributors.
Using the wrong programming cable or adaptor may damage your module, and void your Warranty.
uUSB-PA5-II, 4D-UPA, Programming Cable, (Legacy - uUSB-PA5, uUSB-CE5, uUSB-CE5-2, uUSB-MB5)
PmmC/Firmware or user application code programming should only be carried out using official Programming Cables or Adaptors. Any malfunction because of custom or third party USB to Serial converters or Serial (RS232) to Serial(TTL) level converters will void the warranty. It also applies to all 4D products which require an interface from the PC to the module for testing using 4D Software Test Tools. Using an incorrect programmer could 'brick' your module.
If you have an application that requires you to have an on board programmer, such as in a custom product, please contact our Support team, so the required information can be passed to you so you design a programmer that meets the required spec for programming 4D Processors.